/**
* Assign items
* @param string $id
* @return array
*/
public function actionRevoke($id)
{
$items = Yii::$app->getRequest()->post('items', []);
$model = new Assignment($id);
$success = $model->revoke($items);
Yii::$app->getResponse()->format = 'json';
return array_merge($model->getItems(), ['success' => $success]);
}